This invention relates to keys employed for removing manhole covers and; the like from their frames. In the removal of closely fitting manhole covers from. their frames it is necessary to provide means whereby the joint be- 1 tween the cover and frame is broken before the cover can be lifted or slid out of the frame.

The invention has for its main object to provide an efiicient device for this purpose which will unfailingly break the joint however closely fitting the cover and frame may be.

According to the invention a key for breaking the joint between manhole covers and their frames comprises a key body, an opening bolt carried by the key body and adapted to make lifting engagement with a part of the cover, and screw means also carried by the key body which is actuated to react against the frame and break the joint by the screw action.

It is of advantage to have a single key or a covers from their frames no matter what means, such as keyhole slots, cross-pins or the like, are provided on the cover for the purpose of lifting the latter. For this purpose, according to another feature of the invention interchangeable opening bolts may be provided for fitment to the key body so that mere replacement of one form of opening bolt by another adapts the key to the removal of another type of cover. Further, an attachment may be provided to adapt the keys for opening covers having a central keyhole slot or the like for lifting purposes.

Various embodiments of the invention will now be more particularly described, by'way of example, with reference to the accompanying drawings, in which- Figure 1 is a side elevation of one form of key according to the invention adapted, with the use of interchangeable opening bolts, for the removal from. their frames of manhole covers provided with various lifting means, such as keyhole slots, cross-pins or the like,

Figure 2 is a part-sectional plan view on the line 2-2 of Figure 1,

Figures 3 to 5 are side elevations and plan respectively showing the jackscrew removed from the key of Figures 1 and 2,

Figures 6 and '7 are side elevation and sectional plan respectively of the opening bolt removed from the key of Figure 1,

Figures 8 and 9 are similar views to Figures 6 and 7 respectively of a different form of opening bolt interchangeable with the bolt shown in Figures 6 and '7 in the key of Figures 1 and 2,

Figures 10 to 12 are side elevations. and sectional plan respectively of a further form of opening bolt interchangeable with those of Figures 6. to 9,

Figure. 13 is a side elevation of two, keys of the kind shown. in Figure 1 provided with an attachment to enable. them to remove a manhole cover having central lifting means,

Figure 14 is a side elevation of one of the locking bolts by which. the keys are connected. to the removed from the attachment. of Figure 13, and

Figures 17 and 18 are side elevation and end elevationrespectively of another construction of key especially for use in removing two diiferent types of manhole covers; from their frames.

In the embodiment of the invention shown in Figures 1 and 2-, the key body, which is indicated generally by the reference numeral l9; consists of a malleable casting having a part I90, adapted to lie on the manhole cover near the edge thereof with an upwardly stepped part [919 overhanging the frame. The part l9a lying on the cover is apertured at 20 to receive an opening bolt 2|, which has an end 22 to engage a keyhole slot in the manhole cover, the shank of the opening bolt. being screw threaded at 23. and provided with a nut 24. By this, means the end 22 of the opening bolt making lifting engagement With the cover may be adjusted vertically relatively to the key body l9, so that after the bolt has engaged'the appropriate part of the cover the lattermay be clamped rigidly to the key body to avoid any lost motion during the subsequent cover-removing operation. The upwardly stepped part I91) of the key body is apertured at 2-9 to carry a jackscrew 25 which may be rotated to travel downwardly relatively to the'key body It and contact the frame which forms the reaction to the lifting force exerted. In order to reduce friction and prevent wear of the frame by the rotating end of the jackscrew 25 boring thereinto, the point of the screw carries a small supporting piece 26 which in practice stands stationary on the frame, the screw 25 being rotatable relatively to the supporting piece 26 and having an anti-friction connection therewith at 21. A handle 28 in the form of a loop of steel tubing is preferably welded to the key body IQ for the purpose of lifting the cover after the joint has been broken by operation of the jackscrew 2,5.

In Figures 3 to 5 the jackscrew 25 is shown removed from the aperture 29 in the key body I9 and it will be seen that it carries a block 39 threaded upon its screwed shank. The block 39 is provided for the purpose of locating the jackscrew in the aperture 29 of the key body, being provided with a horizontal keyway 3| cut therein in which a key 32 carried by the body I9 engages when the jackscrew is fitted into the aperture 29. The latter is elongated as shown in Figure 2 so that the distance between the jackscrew 25, when fitted therein, and the opening bolt 2| may be adjusted by sliding the block 30 carrying the jackscrew along the key 32. As shown, the lower rectangular portion 39a of the block projects below the part I9b of the key body, the upper portion 33b of the block which lies within the aperture 29, being U shaped with the closed end of the U directed towards the closed end of the U of the aperture 29 (see Figure 2) in order to permit maximum adjustability of the jackscrew 25 in a direction towards and away from the opening bolt 2|. By this means the key is rendered suitable for use with various types of manhole covers and frames in which the lifting means provided on the cover are at different distances from the edge of the cover.

The opening bolt 2! is shown removed from the aperture 22 in the key body in Figures 6 and '7. This opening bolt is one of a number of interchangeable opening bolts having various types of lower end 22 to engage the various forms of lifting means provided on different types of manhole cover. The opening bolt 2| of Figures 6 and '7 is adapted for use when removing a manhole cover having lifting means in the form of keyhole slots, the horizontally projecting portions 22 at the lower end of the shank being inserted in the keyhole slot of the cover and then turned at right angles so that it lies out of register with the slot. Also provided on the shank of the opening bolt below the screw thread 23 is a projection 33 disposed at right angles to the projecting portion 22, so that with the projection 33 lying within the elongated slot 29 of the key body inadvertent rotation of the opening bolt, to enable its lower end 22 to escape from below the keyhole slot in the manhole cover, is prevented.

By way of example another form of opening bolt is shown in Figures 8 and 9 in which the lower end 22a of the bolt 2Ia is formed as a hook to engage beneath the cross-pin of a manhole cover provided with that type of lifting means. With this hooked opening bolt a cross projection, such as the part 33 of Figure 6, is unnecessary as the hook 22a cannot rotate once it has been engaged beneath the cross-pin. The further form of opening bolt 2Ib illustrated in Figures 10 to 12 is generally similar to the form shown in Figures 6 and 7, being suitable for engaging another somewhat similar design of keyhole slot lifting means with which some manhole covers are provided. The threaded shank 23b is longer than that of the construction already described, as is also the unthreaded portion of the shank, and the lower end 221) is of somewhat different shape, the projecting portions being of less width than the diameter of the shank, as shown in Figure 12. The opening bolt 2Ib, being of considerably greater length than the bolt 2|, may beemployed with very thick covers, that is to say with covers where the lower end 22b of the bolt has to be inserted a considerable depth in the keyhole slot before it may be turned at right'angles out of register with the slot. With this long form of opening bolt 2Ib an open-sided sleeve 36 and a cap 31 are provided; the sleeve may be slipped around the shank of the opening bolt below the cap 31, as shown, to act as a spacer piece. The lower end of the sleeve is provided with outwardly turned arm 38 which straddle the part I9a of the key body, the arms being cut away at 39 to enable full horizontal adjustability of the opening bolt 2Ib, in the elongated aperture or slot 20, the closed side of the sleeve being received in the recess 40 of the key body in this fully adjusted position. When the spacer piece 36 is not required the cap 31 serves as a washer and bears on the part I9a of the key body. It will be understood that these various forms of opening bolt 2|, 2Ia, 2Ib may be readily interchanged in the aperture or slot 20 of the key body I9 merely by removing the respective nuts and washers or caps, withdrawing from the aperture the opening bolt not required and substituting the required design of opening bolt and replacing the nut and washer or cap.

In practice two of the keys described are employed when removing the known closely fitting rectangular covers, such as are described in the specifications of United States Patents Nos. 1,820,127 and 2,109,289 and of the United States patent application Serial No. 129,941, the keys being located above the keyhole slots or the like at one end of the cover to raise that'end before the cover is drawn out of its frame. With the keys properly positioned on the manhole cover and frame and the appropriate opening bolts engaged with the lifting means provided on the cover, the nuts 24 of the opening bolts are screwed down the threads 23 until the manhole cover is clamped rigidly to the key bodies with the top surface of the cover against the lower surfaces of the parts I9a of the keys. The jackscrews 25 are then screwed down until the pieces 26 contact with the frame. Thereafter the jackscrews are screwed down further and alternately, a few turns at a time, so that the end of the manhole cover is raised evenly to break the joint between the cover and its frame, the parts I9u of the keys being of such length beyond the opening bolts and inwardly of the cover as to prevent bending of the opening bolts under the screw action. After the cover has been raised sufficiently to break the joint it may be drawn off with the aid of the handles 28.

Two keys of the construction illustrated in Figures 1 and 2 may be adapted for the removal of the known type of circular or rectangular cover, having a central keyhole slot or cross-pin, from its frame by the provision of an appropriate attachment. Such an adaptation is illustrated in Figure 13 which shows two keys I9 connected together by an attachment 34. The latter consists of a mild steel channel or bridge piece to the ends of which the keys I9 are connected, one at each end, by locking bolts 35 passed through apertures in the bottom wall of the channel or bridge piece 34 near the ends thereof and through the opening bolt holes 20 of the keys. The latter are thereby rigidly attached to the channel member or attachment '34 to for a, bridge spanning the cover and provided with a jackscrew 25 at each end of the bridge for reacting against the frame. The centre part of the channel is apertured to receive an opening bolt 2Ic. The latter is shown removed from the bridge piece in Figures 15 and 16 and is of substantially the same construction as that already described with reference to Figures 10 to 12 except that no space piece is provided and a greator length of the shank is screw threaded at 230. It will be understood that the top wall of the channel or bridge piece 3% is slotted at it into which the handles 28 of the keys pass as shown in Figure 13.

The whole arrangement forms a compact, efficient mechanism for the removal of all types of manhole covers from their frames and avoids the risk of breakage of the well known types of loose fitting covers due to levering up of the cover from its frame by a pickaXe or crowbar.

Another construction of key according to the invention and illustrated in Figures 17 and 18 is designed particular for use in removing two different types of manhole covers from their frames, for example a heavy road type cover and a light pavement type cover. The key comprises two key bodies 19d, we each with its opening bolt 2 id, Ne and jackscrew d, 256 respectively. The key body 59d is adapted for removing heavy road type covers and the key body I96 for light pavement type covers. The key bodies IM and use are connected by a 100p of steel tubing 28a. with which they form a U-shaped construction, the open end of which is closed by a rod. d2 welded to the ends of the arms of the U. The complete key is therefore stirrup-shaped. Assuming a heavy road type cover is to be removed, the key is laid horizontally with the heavy road type key body l9d resting upon the cover and frame. In this position the light pavement type key body I96, which is not used in this operation, is located above the operative heavy road type key body. When a light pavement type cover is to be removed the key is used in the inverted position. The key breaks the joint between the cover and frame in the manner already described and the construction and arrangement of the opening bolts Zld, 25c and jackscrews 25d, 256, are substantially as described above. However, if desired, the jackscrews may be of simplified form, each consisting of an ordinary headed screw passing through a screwed aperture 26d or Zlle in the respective key body and provided with a bearing ball 26d or we received in a recess in the point of the screw and projecting slightly therefrom. This bearing ball prevents the jackscrew boring. into the manhole frame in a simple and effective manner. The opening bolts Md and Zle have lower ends 22d and 226 adapted, to co-operate with lifting means of a modified keyhole slot type and are headed similarly to the jackscrews.

What I claim and desire to secure by Letters Patent is:

1. A key for breaking the joint between a manhole cover and its frame comprising in combination a key body, opening means carried by said key body and adapted to make lifting engagement with a part of and clamp the key body rigidly to the cover, and screw means also carried by the key body which are spaced from the opening means to react against the frame and break the joint by the screw action.

2. A key for breaking the joint between a manhole cover and its frame comprising in combination a key body, opening means carried by said key body and adapted to make lifting engagement with a part of the cover, means associated with said opening means operable to clamp said key body rigidly to the cover, and screw means also carried by the key body which are spaced from the opening means to react against the frame and break the joint by the screw action.

3. A key for breaking the joint between a manhole cover and its frame comprising a key body having a portion adapted to engage the upper face of a manhole cover, opening means having at one end thereof a member adapted to enter an opening in and interlock with said cover, and at the other end thereof actuating means whereby said opening member may be actuated to rigidly attach said body to a cover, said body having another portion spaced so as to overhang the frame about said cover, and lifting means mounted for vertical movement in said last named portion of the body and adapted to ex ert vertical pressure against the frame to lift said body and the cover through said opening means.

4. A key for breaking the joint between a manhole cover and its frame comprising a key body having a portion adapted to engage the upper face of a manhole cover, opening means having at one end thereof a member adapted to enter an opening in and interlock with said cover, and at the other end thereof actuating means whereby said opening member may be actuated to rigidly attach said body to a cover, said body having another portion spaced so as to overhang the frame about said cover, lifting means mounted for vertical movement in said last named portion of the body and adapted to exert vertical pressure against the frame to lift said body and the cover through said opening means, and relatively adjustable supports for said opening means and said lifting means whereby said key is adapted for use with differently constructed manhole covers.

5. A key for breaking the joint between a manhole cover and its frame comprising a key body having a portion adapted to engage the upper face of a manhole cover, opening means having at one end thereof a member adapted to enter an opening in and interlock with said cover, and at the other end thereof actuating means whereby said opening member may be actuated to rigidly attach said body to a cover, said body hav-' ing another portion spaced so as to overhang the frame about said cover, lifting means mounted for vertical movement in said last named portion of the body and adapted to exert vertical pressure against the frame to lift said body and the cover through said opening means, and a handle upon said body whereby the cover may be lifted by means of the key after the joint between the cover and its frame has been broken. 7

6. A key for breaking the joint between a manhole cover and its frame comprising a bridge member having portions adjacent the opposite ends thereof adapted to engage diametrically opposite portions of a manhole cover, handles connected with the opposite ends of said bridge I member, opening means carried by said bridge

US2249603A1938-12-151939-12-12Key for removing manhole covers and the like from their frames
Expired - LifetimeUS2249603A
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